<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Document</title>
  <style>
    body {
      height: 1000px;
    }
    #ts {
      position: absolute;
    }
  </style>
</head>
<body>
  <img src="images/tianshi.gif" id="ts" alt="">
  <script>
    var ts = document.getElementById('ts');
    document.onmousemove = function (e) { 
      e = e || window.event;
      // ts.style.left = e.clientX - 10 + 'px';
      // ts.style.top = e.clientY - 10 + 'px';

      ts.style.left = e.pageX - 10 + 'px';
      ts.style.top = e.pageY - 10 + 'px';
    }
  </script>
</body>
</html>
